Here are the maximum random 4k read and write scores from Iometer, with a queue depth of 32 and executed within an 8GB block. The test is executed with compressible data.
In the release nots of the M5 Pro Xtreme firmware Plextor mentions this test, claiming it can achieve 100.000 Iops. We arrived at 96.136, only slightly more than the 92k from last time.
The M5S got to 72.974 Iops.